Global ridesharing service Uber said Friday it had raised $200 million in additional funding to help its push into emerging markets.

The latest round comes from Luxembourg-based investment group LetterOne (L1), according to a joint statement.

"Our goal is simple: reliable and affordable transportation everywhere, for everyone, at the push of a button," said Uber chief executive Travis Kalanick.

"L1's knowledge of emerging markets will be crucial in helping us make cities more accessible, opening up more possibilities for riders and more opportunities for drivers."

Mikhail Fridman, the Russian billionaire who is chairman of L1, said he was excited about the strategic partnership with Uber.

"As entrepreneurs, with experience in retail, banking, telecoms and energy sectors, and knowledge of diverse developed and emerging markets, we believe that Uber's highly talented management team possesses the necessary vision and skills to build the company into one of the world's preeminent technology businesses," said Fridman, whose group also holds stakes in telecom groups VimpelCom and Turkcell.

San Francisco-based Uber, which allows individuals to offer rides via a smartphone application, has expanded to hundreds of cities worldwide and more than 60 countries, drawing protests from the taxi industry and regulators.

The company has become one of the biggest venture-backed startups, with a valuation of more than $50 billion based on private investment disclosed to date, with some reports saying the valuation is over $60 billion.